Battery cell with increased tab area and method and apparatus for manufacturing same

ABSTRACT

A method of forming batteries includes feeding a foil through a coating machine. The movement of the foil defines a foil direction. The method applies a first coating band and a second coating band to the foil. The second coating band is spaced from the first coating band by a first tab gap. The foil is cut substantially perpendicular to the foil direction to separate a first coated blank. The first coated blank is cut separate the first coating band and a first portion of the first tab gap, and to separate the second coating band and a second portion of the first tab gap. A first electrode is formed from the first coating band and the first portion of the first tab gap, and a second electrode is formed from the second coating band and the second portion of the first tab gap.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of application Ser. No. 15/651,354,filed Jul. 17, 2017, which is hereby incorporated by reference in itsentirety.

INTRODUCTION

This disclosure generally relates to lithium ion batteries, which are aclass of rechargeable batteries in which lithium ions move between anegative electrode (i.e., anode) and a positive electrode (i.e.,cathode). Liquid and polymer electrolytes can facilitate the movement oflithium ions between the anode and cathode.

SUMMARY

A lithium ion battery cell or module is provided. A plurality of thelithium ion battery modules or mono cells may be incorporated into abattery pack. The battery pack may be used with a powertrain. A firstmono cell includes a first electrode foil having a first body and afirst tab. The first body has long edges defining a length, and shortedges defining a width. A ratio of the length to width of the first bodyis at least two. However, in some configurations, the ratio of thelength to width of the first body is at least five.

The first tab extends from one of the long edges of the first body. Thefirst tab is entirely between one of the short edges of the first bodyand a midpoint of the long edge. A first coating is formed of one of ananode material and a cathode material, and substantially covers at leastone side of the first body of the first electrode foil.

A second electrode foil has similar structural features to the firstelectrode foil. A second coating is formed of the other of the anodematerial and the cathode material, and substantially covers the secondbody of the second electrode foil. A second tab extends from one of thelong edges of the second body. The second tab of the second electrodefoil is oriented opposite the first tab of the first electrode foil.

A tab length of the first tab and the second tab may be at least 45percent of the length of the first body and the second body,respectively. A tab height of the first tab and the second tab may be atleast 20 percent of the width of the first body and the second body,respectively.

A second mono cell includes a third electrode foil and a third coating,and a fourth electrode foil and a fourth coating. The third electrodefoil has a third body having long edges defining a length, and shortedges defining a width, and a ratio of the length to width is at leastfive. A third tab extends from one of the long edges, entirely betweenone of the short edges and a midpoint of the long edge, and has a thirdtab length of at least 45 percent of the length of the third body. Athird coating is formed of one of an anodic material and a cathodicmaterial and substantially covers the third body of the third electrodefoil.

The fourth electrode foil has a fourth body with long edges defining alength, and short edges defining a width, and a ratio of the length towidth is at least five. A fourth tab extends from one of the long edges,entirely between one of the short edges and a midpoint of the long edge,and has a fourth tab length of at least 45 percent of the length of thefourth body. The fourth tab of the fourth electrode foil is opposite thethird tab of the third electrode foil relative to the fourth body. Thefourth coating is formed of the other of the anodic material and thecathodic material substantially covering the fourth body of the fourthelectrode foil.

The first tab of the first mono cell and the third tab of the secondmono cell are on opposing sides of the midpoint of the long edge of therespective first body and third body. Similarly, the second tab of thefirst mono cell and the fourth tab of the second mono cell are onopposing sides of the midpoint of the long edge of the respective secondbody and fourth body.

A method, and associated apparatus, for forming battery electrodes arealso provided. The method includes feeding a foil, or foil coil, througha coating machine. Movement of the foil defines a foil direction.

A first coating band is applied to the foil, and a second coating bandis applied to the foil. The second coating band is spaced from the firstcoating band by a first tab gap, which is a portion of the foil that isnot coated by the coating machine.

The foil is cut substantially perpendicular to the foil direction toseparate a first coated blank. The first coated blank is cut or notchedto separate the first coating band and a first portion of the first tabgap from the second coating band and a second portion of the first tabgap. Therefore, a first electrode is formed from the first coating bandand the first portion of the first tab gap, and a second electrode isformed from the second coating band and the second portion of the firsttab gap.

The above features and advantages, and other features and advantages, ofthe present subject matter are readily apparent from the followingdetailed description of some of the best modes and other configurationsfor carrying out the disclosed structures, methods, or both.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a portion of a battery or batterycell, illustrating first and second mono cells formed from first andsecond electrodes.

FIG. 2A is a schematic front view of a mono cell, such as the first monocell shown in FIG. 1.

FIG. 2B is a schematic front view of a mono cell, such as the secondmono cell shown in FIG. 1.

FIG. 2C is a schematic front view of a stack of mono cells, such thoseshown in FIGS. 2A and 2B, joined by bus bars to form a battery cell thatcan be connected to a module.

FIG. 3 is a schematic diagram of a powertrain having a battery packformed from battery cells, such as those shown in FIGS. 1-2C.

FIG. 4 is a schematic processing diagram illustrating one method andapparatus for producing electrodes, such as those shown in FIGS. 1-2C.

DETAILED DESCRIPTION

In the drawings, like reference numbers correspond to like or similarcomponents whenever possible throughout the several figures. There isshown in FIG. 1 a schematic, diagrammatic view of a portion of a batterycell or a battery module 10, which may be a lithium ion battery or aportion of a lithium ion battery.

The portion of the battery module 10 shown in FIG. 1 has two lithium ionbattery mono cells, a first mono cell 12 and a second mono cell 14. Notethat the battery module 10 likely includes many additional mono cells.Portions of the first mono cell 12 and the second mono cell 14 areinsulated by one or more separators 16, which may be planar or may be aZ-type separator 16, as illustrated by the dashed portions of theseparators 16.

As used herein, the term “mono cell” refers to the most basic unit ofthe lithium ion battery, which has two electrodes and is capable ofoperating as a battery. In some situation, the term “cell” may also beused to refer to the basic unit, or may be used to refer to a number ofmono cells, particularly when the mono cells are connected by a commonpositive bus structure and a common negative bus structure, in parallel.In such a situation, multiple cells may be assembled, in series orparallel, to form a module. Therefore, in some situations, the term cellmay be used as either an equivalent to the use of mono cell, herein, oras an intermediate unit between mono cell and module. However, as usedherein, the term “module” is used to refer to a plurality ofoperatively-connected mono cells, such that FIG. 1 illustrates a moduleby having more than one mono cell. Generally, the term “pack” refers toa plurality of operatively-connected modules.

Much of the description herein refers to lithium ion battery components.However, the structures, methods, and apparatuses described herein maybe applied to other battery chemistry types.

The structures of FIG. 1 are basic illustrations, and the portion of thebattery module 10 illustrated may be part of a larger module. Themodule, or smaller portions thereof, may be encased or encapsulated incontainer, which can be a hard (e.g., metallic) case or soft pouch(e.g., multiple layers of polymer, multiple layers of metal sheet, orcombinations thereof). Furthermore, the portions of the battery module10 shown may be surrounded by an electrolyte. Multiple modules may beassembled and operatively connected to form a battery pack, such as maybe used in a hybrid or electric vehicle.

While the present disclosure may be described with respect to specificapplications or industries, those skilled in the art will recognize thebroader applicability of the disclosure. Those having ordinary skill inthe art will recognize that terms such as “above,” “below,” “upward,”“downward,” et cetera, are used descriptively of the figures, and do notrepresent limitations on the scope of the disclosure, as defined by theappended claims. Any numerical designations, such as “first” or “second”are illustrative only and are not intended to limit the scope of thedisclosure in any way.

Features shown in one figure may be combined with, substituted for, ormodified by, features shown in any of the figures. Unless statedotherwise, no features, elements, or limitations are mutually exclusiveof any other features, elements, or limitations. Furthermore, nofeatures, elements, or limitations are absolutely required foroperation. Any specific configurations shown in the figures areillustrative only and the specific configurations shown are not limitingof the claims or the description.

Each of the first mono cell 12 and the second mono cell 14 includes apositive electrode 22 and a negative electrode 24. The positiveelectrode 22 may be referred to as the cathode and the negativeelectrode 24 may be referred to as the anode. Either of the electrodes,or portions thereof, may be referred to numerically as, for example,first, second, third, and so on. The positive electrode 22 and thenegative electrode 24 are generally formed of foils and intercalationmaterials, which may be applied to the foils as coatings.

A first electrode foil, which may be referred to as a cathode foil or apositive foil 30, has a first body 32 and a first tab 34. In someconfigurations, the positive foil 30 may be formed from, for example andwithout limitation, aluminum or aluminum alloys. A first coating,cathode coating, or positive coating 36 may be formed of a cathodicmaterial and substantially covers the first body 32 of the positive foil30. As shown in FIG. 1, the positive coating 36 may be applied to bothsides of the first body 32, such that electrons may move to and fromboth sides of the first body 32.

A second electrode foil, which may be referred to as an anode foil or anegative foil 40, has a second body 42 and a second tab 44. In someconfigurations, the negative foil 40 may be formed from, for example andwithout limitation, copper or copper alloys. A second coating, anodecoating, or negative coating 46 may be formed of an anodic materialsubstantially covering the second body 42 of the negative foil 40. Thepositive coating 36 and the negative coating 46 are intercalationmaterials. Note that the positive coating 36 and the negative coating 46are illustrated in FIG. 1 with hatch marks to better identify thedifferent materials. However, the view of FIG. 1 is not a cross section.

As used herein, the term substantially, refers to relationships thatare, ideally perfect or complete, but where manufacturing realtiesprevent absolute perfection. Therefore, substantially denotes typicalvariance from perfection. For example, if height A is substantiallyequal to height B, it would be preferred that the two heights are 100.0%equivalent, but manufacturing realities likely result in the distancesvarying from such perfection. Skilled artisans would recognize theamount of acceptable variance.

For example, coverages, areas, or distances may generally be within 10%of perfection for substantial equivalence. Similarly, relativealignments, such as parallel or perpendicular, may generally beconsidered to be within 5%.

Exemplary operation and chemical composition of the battery module 10 isdescribed herein. However, these details are for illustrative purposesonly. Skilled artisans will recognize various alternative materials andoperating mechanisms, and the descriptions herein are not limiting theconfigurations explicitly discussed.

The negative electrode 24 may include lithium and the positive electrode22 may include sulfur. Generally, the positive coating 36 is capable ofstoring lithium ions at a higher electric potential than the negativecoating 46. The positive foil 30 and the negative foil 40 are connectedby an interruptible, external, circuit that allows an electric currentto pass between the positive electrode 22 and the negative electrode 24to electrically balance the related migration of lithium ions within thebattery module 10. Although FIG. 1 illustrates negative coating 46 andpositive coating 36 schematically for the sake of clarity, negativecoating 46 and positive coating 36 may be an exclusive interface betweenthe negative electrode 24 and the positive electrode 22, respectively,and the electrolyte.

The negative coating 46 may include, for example and without limitation,any lithium host material configured to sufficiently undergo lithium ionintercalation, deintercalation, and alloying, while functioning as thenegative terminal of the battery module 10. The negative coating 46 mayalso include a polymer binder material to structurally hold the lithiumhost material together. For example, in one configuration, negativecoating 46 may include graphite intermingled in one or more ofpolyvinyldiene fluoride (PVdF), an ethylene propylene diene monomer(EPDM) rubber, carboxymethoxyl cellulose (CMC), and styrene,1,3-butadiene polymer (SBR).

Graphite and carbon materials may be used in the negative electrode 24because it exhibits favorable lithium ion intercalation anddeintercalation characteristics, is relatively non-reactive, and able tostore lithium ions in quantities that produce a relatively high energydensity. Other materials may be also be used to form the negativecoating 46, including, for example and without limitation, one or moreof lithium titanate, silicon, silicon oxide, tin, and tin oxide.

The negative foil 40 may include, for example and without limitation,copper, aluminum, stainless steel, or another appropriate electricallyconductive material, as recognized by skilled artisans. The negativefoil 40 may be treated (e.g., coated) with highly electricallyconductive materials, including, for example and without limitation, oneor more of conductive carbon black, graphite, carbon nanotubes, carbonnanofiber, graphene, and vapor growth carbon fiber (VGCF), among others.

The positive coating 36 may include, for example and without limitation,any lithium-based active material configured to sufficiently undergolithium intercalation and deintercalation while functioning as thepositive terminal of one of the cells of the battery module 10. Positivecoating 36 may also include a polymer binder material, an ethylenepropylene diene monomer (EPDM) rubber, carboxymethoxyl cellulose (CMC),and styrene, 1,3-butadiene polymer (SBR), to structurally hold thelithium-based active material together.

The positive coating 36 may be formed from layered lithium transitionalmetal oxides. In some configurations, the positive coating 36, forexample and without limitation, one or more of spinel lithium manganeseoxide (LiMn2O4), lithium cobalt oxide (LiCoO2), anickel-manganese-cobalt oxide [Li(NixMnyCoz)O2], or a lithium ironpolyanion oxide such as lithium iron phosphate (LiFePO4) or lithium ironfluorophosphate (Li2FePO4F) intermingled in at least one ofpolyvinyldiene fluoride (PVdF), an ethylene propylene diene monomer(EPDM) rubber, carboxymethoxyl cellulose (CMC), and styrene,1,3-butadiene polymer (SBR).

Other lithium-based active materials can also be utilized besides thosemention. Alternative materials include, but are not limited to, lithiumnickel oxide (LiNiO2), lithium aluminum manganese oxide (LixAlyMn1-yO2),and lithium vanadium oxide (LiV2O5).

The positive foil 30 may include, for example and without limitation,aluminum or another appropriate electrically conductive material, aswould be recognized by skilled artisans. The positive foil 30 may betreated (e.g., coated) with highly electrically conductive materials,including, for example and without limitation, one or more of conductivecarbon black, graphite, carbon nanotubes, carbon nanofiber, graphene,and vapor growth carbon fiber (VGCF).

The components shown in the figures may be in contact with anappropriate electrolyte solution configured to conduct lithium ionsbetween the negative electrode 24 and the positive electrode 22 withinthe battery module 10. In one configuration, the electrolyte solutioncan be a non-aqueous liquid electrolyte solution that includes, forexample and without limitation, a lithium salt dissolved in an organicsolvent or a mixture of organic solvents. Illustrative lithium saltsthat can be dissolved in an organic solvent to form the non-aqueousliquid electrolyte solution include, for example and without limitation:LiClO4, LiAlCl4, LiI, LiBr, LiSCN, LiBF4, LiB(C6H5)4 LiAsF6, LiCF3SO3,LiN(CF3SO2)2, LiPF6, and mixtures or combinations thereof. Illustrativeorganic solvents include, for example and without limitation: cycliccarbonates (ethylene carbonate, propylene carbonate, butylenecarbonate), acyclic carbonates (dimethyl carbonate, diethyl carbonate,ethylmethylcarbonate), aliphatic carboxylic esters (methyl formate,methyl acetate, methyl propionate), γ-lactones (γ-butyrolactone,γ-valerolactone), chain structure ethers (1,2-dimethoxyethane,1-2-diethoxyethane, ethoxymethoxyethane), cyclic ethers(tetrahydrofuran, 2-methyltetrahydrofuran), and mixtures thereof.

The separator 16 may be a microporous polymer, including, for exampleand without limitation, a polyolefin. The polyolefin may be ahomopolymer (derived from a single monomer constituent) or aheteropolymer (derived from more than one monomer constituent), eitherlinear or branched. For example, and without limitation, the polyolefincan be polyethylene (PE), polypropylene (PP), or a blend of PE and PP.The separator 16 may, optionally, be ceramic-coated with materialsincluding, for example and without limitation, one or more of ceramictype aluminum oxide (e.g., Al2O3), and lithiated zeolite-type oxides,among others. Lithiated zeolite-type oxides may be used to enhance thereliability and cycle life performance of lithium ion batteries, such asthe battery module 10.

The separator 16 may be a single layer or a multi-layer microporouspolymer laminate, fabricated from either a dry or wet process. Forexample, in one configuration, a single layer of the polyolefin may formthe entirety of the separator 16. In another configuration, however,multiple discrete layers of similar or dissimilar polyolefins may beassembled into the separator 16. The separator 16 may also include otherpolymers in addition to the polyolefin such as, but not limited to,polyethylene terephthalate (PET), polyvinylidene fluoride (PVdF), and ora polyamide (Nylon). The polyolefin layer, and any other optionalpolymer layers, may further be included in the separator 16 as a fibrouslayer to help provide the separator 16 with appropriate structural andporosity characteristics.

The battery module 10 generally operates by reversibly passing lithiumions between the negative electrode 24 and the positive electrode 22.Lithium ions move from the positive electrode 22 to the negativeelectrode 24 while charging, and move from the negative electrode 24 tothe positive electrode 22 while discharging. At the beginning of adischarge, the negative electrode 24 generally contains a highconcentration of intercalated lithium ions while the positive electrode22 is relatively depleted, such that establishing a closed externalcircuit between the negative electrode 24 and the positive electrode 22under such circumstances causes intercalated lithium ions to beextracted from the negative electrode 24. The extracted lithium atomsare split into lithium ions and electrons as they leave an intercalationhost at an electrode-electrolyte interface.

The lithium ions are carried through the micropores of the separator 16from the negative electrode 24 to the positive electrode 22 by theionically conductive electrolyte while, at the same time, the electronsare transmitted through the external circuit from the negative electrode24 to positive electrode 22 to balance the overall electrochemical cell.Flow of electrons through the external circuit can be harnessed and fedto a load device until the level of intercalated lithium in the negativeelectrode falls below a workable level or the need for power ceases.

The battery module 10 may be recharged after a partial or full dischargeof its available capacity. To charge or re-power the lithium ion cellsof the battery module 10, an external power source is connected betweenthe positive electrode 22 and the negative electrode 24 to drive thereverse of the discharge electrochemical reactions. That is, duringcharging, the external power source extracts the lithium ions present inthe positive electrode 22 to produce lithium ions and electrons. Thelithium ions are carried back through the separator 16 by theelectrolyte solution, and the electrons are driven back through theexternal circuit, both towards the negative electrode 24. The lithiumions and electrons are ultimately reunited at the negative electrode,thus replenishing it with intercalated lithium for future celldischarge.

The lithium ion battery module 10, or a battery module or packcomprising a plurality of battery cells connected in series and/or inparallel, can be utilized to reversibly supply power and energy to anassociated load device. Lithium ion batteries may be used in variouselectronic devices (e.g., laptop computers, cameras, radios, minedetectors, and cellular/smart phones), aircrafts, and satellites, amongothers. Lithium ion batteries, modules, and packs may be incorporatedinto vehicles, such as a hybrid electric vehicle (HEV), a batteryelectric vehicle (BEV), a plug-in HEV, or an extended-range electricvehicle (EREV) to generate enough power and energy to operate one ormore systems of the vehicle. For instance, the battery cells, modules,and packs may be used in combination with a gasoline or diesel internalcombustion engine to propel the vehicle (such as in hybrid electricvehicles), or may be used alone to propel the vehicle (such as inbattery powered vehicles).

The battery module 10 may be used in any rolling platform, including,without limitation: motorcycles, boats, tractors, buses, motorcycles,mobile homes, campers, and tanks. Furthermore, they components describedherein may also be used in a variety of other industries andapplications, including, without limitation: aerospace applications,consumer goods, industrial and construction equipment, farm equipment,or heavy machinery.

Referring also to FIGS. 2A, 2B, and 2C, and with continued reference toFIG. 1, there are shown additional views of portions of the batterymodule 10 shown in FIG. 1. FIG. 2A schematically illustrates a side viewof the first mono cell 12, and FIG. 2B schematically illustrates a sideview of the second mono cell 14. FIG. 2C schematically illustrates aside view of a plurality of mono cells.

FIG. 2A shows a side view of the first mono cell 12, with only theseparator 16 between the positive electrode 22 and the negativeelectrode 24. The first body 32 of the positive foil 30 has long edges50 defining a length 52 and short edges 54 defining a width 56.Similarly, the second body 42 of the negative foil 40 has long edges 50defining the length 52 and short edges 54 defining the width 56.

Note that in the view of FIGS. 2A and 2B, the coatings are blocking thebodies from view. In particular, the negative coating 46 issubstantially covering the second body 42, such that neither the firstbody 32 nor the second body 42 is viewable in FIGS. 2A and 2B. However,the long edges 50 and the short edges 54 are substantially coincidentwith the negative coating 46. Therefore, the length 52 and the width 56may be measured from the negative coating 46, as it has substantiallythe same dimension as the second body 42 and the first body 32.

A ratio of the length 52 to the width 56 of the first body 32 and thesecond body 42 is at least three. However, in many configurations, suchas that shown in FIGS. 2A and 2B, the ratio of the length 52 to thewidth 56 is greater than five. For example, the overall length of thefirst mono cell 12 and the second mono cell 14 may be approximately 600millimeters. In such a configuration, the length 52 may be approximately590 millimeters and the width 56 may be approximately 110 millimeters.

As viewable in FIG. 2A, the first tab 34 extends from one of the longedges 50 of the first body 32. The first tab 34 is entirely between oneof the short edges 54 and a midpoint 60 of the long edge 50. Therefore,the first tab 34 is asymmetric about the first body 32.

Similarly, the second tab 44 extends from one of the long edges 50 ofthe second body 42. The second tab 44 is entirely between one of theshort edges 54 and a midpoint 60 of the long edge 50, such that thesecond tab 44 is also asymmetric about the second body 42. Note that,when assembled into the first mono cell 12, the second tab 44 is on theopposing side of the first mono cell 12 from the first tab 34, relativeto the respective coatings and the bodies.

By orienting the first tab 34 and the second tab 44 on the long edges50, the distance that electrons are required to travel through thepositive foil 30 and the negative foil 40, respectively, may be reducedrelative to other configurations. For example, other configurations mayhave tabs extending from the short edges 54, such that electrons may beforced to travel the entire length 52 to reach the first tab 34 of thesecond tab 44 and be carried into the external circuit.

As viewable in FIG. 2B, the second mono cell 14 has substantially thesame features. However, the positive electrode 22 and the negativeelectrode 24 of the second mono cell 14 are flipped horizontally (asviewed in the figures) relative to the orientation of the first monocell 12. Note that, in the viewpoint of FIG. 1, the first tab 34 and thesecond tab 44 of the first mono cell 12 are in the foreground, while thefirst tab 34 and the second tab 44 of the second mono cell 14 are in thebackground. Any of the elements of the second mono cell 14 that aredesignated as first and second may also be referred to as third andfourth.

As described herein, the positive electrode 22 and the negativeelectrode 24 may be produced in such a manner that they can be placedinto any of the orientations shown herein, in spite of the asymmetricnature of the first tab 34 and the second tab 44. This allows sharedequipment to produce the positive electrode 22 for either the first monocell 12 or the second mono cell 14 and to produce the negative electrode24 for either the first mono cell 12 or the second mono cell 14.

As illustrated in FIGS. 2A and 2B, the first tab 34 defines a first tablength 62, and the second tab 44 defines a second tab length 64. Thefirst tab length 62 may be at least 45 percent of the length 52 of thefirst body 32, and the second tab length 64 may be at least 45 percentof the length 52 of the second body 42.

The relatively large length of the first tab 34 and the second tab 44reduces the current density flowing through the first tab 34 and thesecond tab 44 during operation of the battery module 10. Additionally,as described herein, having the first tab 34 and the second tab 44 atnearly half the size of the length 52 of the respective bodies reducesthe amount of waste created by manufacturing the positive electrode 22and the negative electrode 24.

As illustrated in FIGS. 2A and 2B, a first tab height 66 of the firsttab 34 is at least 20 percent of the width 56 of the first body 32.Similarly, a second tab height 68 of the second tab 44 is at least 20percent of the width 56 of the second body 42. The relatively large tabheight provides room for welding the first tab 34 and the second tab 44to bus structures and improves heat dissipation from the positive foil30 and the negative foil 40.

As shown in FIG. 2C, the first mono cell 12, the second mono cell 14,and a plurality of additional cells may be stacked to form some, or all,of the battery module 10. Repeated units of the first mono cell 12 andthe second mono cell 14 may be used to form the battery module 10, whichmay then be encased in a pouch structure or located with a plurality ofother battery modules to form a battery pack. In FIG. 2C, the secondmono cell 14 is in the foreground and the first mono cell 12 is in thebackground.

A positive bus, or bus bar, which may be referred to as a first bus 72,electrically connects the first tabs 34 of the positive foils 30. Anegative bus, or bus bar, which may be referred to as a second bus 74,electrically connects the second tabs 44 of the negative foils 40. Thefirst tabs 34 and the second tabs 44 may be welded together, and thenwelded to the first bus 72 and the second bus 74, respectively.Alternatively, the first tabs 34 and the second tabs 44 may be directlywelded to the first bus 72 and the second bus 74, respectively. Thefirst bus 72 and the second bus 74 provide connections for multipleelectrodes to battery controllers and exterior circuits, such as loads,generators, or combinations thereof.

Referring also to FIG. 3, and with continued reference to FIGS. 1-2C,there is schematically illustrated a powertrain 80, which may beincorporated into many types of vehicles, including those discussedherein. The powertrain 80 is highly schematic and would likely includenumerous other components and elements.

A battery pack 82 is formed from multiple units of the battery modules10, in various combinations of series and parallel connections, may beused within the powertrain 80. For example, and without limitation, thebattery pack 82 may be used in an electric vehicle, a hybrid vehicle, ora plug-in hybrid vehicle. The battery pack 82 may be operativelyconnected, such as through a powertrain control module 84, to a motorand a generator, or to a combined motor/generator 86. Therefore, thebattery pack 82 may receive and store electrical energy from either agrid or by conversion of kinetic energy in the motor/generator 86, ormay output electrical energy to be converted to kinetic energy by themotor/generator 86. One or more traction devices 88 may berepresentative of, for example and without limitation: wheels or treads.

A battery pack 82 is formed from multiple units of the battery modules10, in various combinations of series and parallel connections, can beutilized by lithium metal batteries (e.g., Li-S batteries) andlithium-ion batteries, and lend numerous advantageous to thereto,including improved (i.e., more uniform) current distribution allowingfast charge and discharge, increased thermal dissipation, reducedresistance, and reduced or eliminated lithium plating, among others. Theshortest traveling distance of electron between the negative andpositive terminals promotes the fast charge and discharge of lithium andlithium ion in the battery. In general, the ease with which lithium ionsare reduced may create undesired lithium plating within lithium-basedbatteries.

Referring also to FIG. 4, and with continued reference to FIGS. 1-3,there is schematically illustrated an apparatus 110 and method forforming battery electrodes, such as those shown in FIGS. 1-3. FIG. 4 ishighly schematic, and portions thereof may not be illustrated at thesame scale as other portions. The apparatus 110 includes a coatingmachine 112 and multiple trimming, cutting, or notching components. Thecutting components are illustrated by cutting lines, but are notseparately shown.

The apparatus 110, and methods of using the same, may be describedrelative to the positive electrode 22 and the negative electrode 24shown and discussed in FIGS. 1-3. However, the apparatus 110 may be usedto manufacture other structures and the positive electrode 22 and thenegative electrode 24 may be manufactured via other means.

The apparatus 110 feeds a foil 114 through the coating machine 112. Thefoil 114 may be configured as a roll. As the foil 114 moves, the coatingmachine 112 deposits layers of coating onto the foil 114. Movement ofthe foil 114 defines a foil direction 116. The foil 114 may be formedfrom the base material for either the positive foil 30 or the negativefoil 40.

The coating machine 112 applies at least a first coating band 122 and asecond coating band 124 to the foil 114. The second coating band 124 isspaced from the first coating band 122 by a first foil gap or first tabgap 132, which is an uncoated portion of the foil 114.

The materials of the first coating band 122 and the second coating band124 may be either the positive coating 36 or the negative coating 46.Additionally, the coatings may be built up, such that the coatingmachine 112 deposits multiple, thin, layers on the foil 114.

The apparatus 110 cuts the foil 114 substantially perpendicular to thefoil direction 116. This separates a first coated blank 142 from thefoil 114. The first coated blank 142 includes the first coating band122, the second coating band 124—or a portion of the second coating band124, as shown in FIG. 2—and the first tab gap 132. Additionally,edge-trimming operations may be cutting excess portions of the foil 114as the coatings are applied, as shown in FIG. 4.

The first coated blank 142 may then be cut or notched, such as with alaser or a die cutting press. Notching the first coated blank 142separates the first coating band 122 and a first portion of the firsttab gap 132 from the second coating band 124 and a second portion of thefirst tab gap 132. At this point, a first electrode 152 is formed fromthe first coating band 122 and the first portion of the first tab gap132, and a second electrode 154 is formed from the second coating band124 and the second portion of the first tab gap 132.

The first electrode 152 and the second electrode 154 are substantiallyidentical, and either may be or rotated into identical positions.Furthermore, if substantially the same coating is applied to both thefront and back (as viewed relative to the orientation of FIGS. 2A and2B) of the foil 114, then the first electrode 152 and the secondelectrode 154 may also be flipping without altering function. Therefore,both the first electrode 152 and the second electrode 154 may be, forexample, the positive electrode 22 for either the first mono cell 12 orthe second mono cell 14, because the location of the first tab 34 may beflipped to either the left side (first mono cell 12) or the right side(second mono cell 14).

The first electrode 152 and the second electrode 154 may besubstantially similar to either the positive electrode 22 or thenegative electrode 24 shown in FIGS. 1-3. A length of the firstelectrode 152 and the second electrode 154 is aligned with the foildirection 116, and may be substantially equal to the length 52 of thepositive electrode 22 or the negative electrode 24. A width of the firstelectrode 152 and the second electrode 154 is substantiallyperpendicular to the foil direction 116, and may be substantially equalto the width 56 of the positive electrode 22 or the negative electrode24. Therefore the first electrode 152 and the second electrode 154 alsohave a length-to-width ratio of at least five. Where the process of FIG.4 is used to create the positive electrodes 22, a substantially similarprocess may be used to feed a second foil through the same or adifferent coating machine to deposit a negative coating and create thenegative electrodes 24.

As shown in FIG. 4, the first portion and the second portion of thefirst tab gap 132 substantially equal the entire first tab gap 132.Therefore, the two resulting tabs, which are equivalent to the first tab34 or the second tab 44 shown in FIGS. 1-3, formed on the firstelectrode 152 and the second electrode 154 are formed with little, orno, waste of the foil 114.

As shown in FIG. 4, the second coating band 124 is at least twice aswide as the first coating band 122. Therefore, additional electrodes maybe formed from the same foil 114 moving in the same foil direction 116.

The coating machine 112 also applies a third coating band 126, which isspaced from the second coating band 124 by a second foil gap or secondtab gap 134. The apparatus 110 cuts or slits the second coating band 124substantially parallel to the foil direction 116. Sitting through thesecond coating band 124 separates the first coating band 122, the firsttab gap 132, and a portion of the second coating band 124 into a firstroll, and separates the third coating band 126, the second tab gap 134,and the remainder of the second coating band 124 into a second roll.

The second roll is cut substantially perpendicular to the foil direction116 to separate a second coated blank 144. The second coated blank 144is then notched to separate the third coating band 126 and a thirdportion of the second tab gap 134 from the remainder of the secondcoating band 124 and a fourth portion of the second tab gap 134.

The third portion and the fourth portion of the second tab gap 134 aresubstantially equal to the entire first tab gap 132. Therefore, a thirdelectrode 156 is formed from the third coating band 126 and the thirdportion of the second tab gap 134, and a fourth electrode 158 is formedfrom the remainder of the second coating band 124 and the fourth portionof the second tab gap 134.

The apparatus 110 may be used to create multiple electrodes that have alength of nearly 600 millimeters, in spite of the fact that theoperative width of the coating machine 112 may be less than 600millimeters. By orienting the electrode length with the foil direction116, the apparatus 110 is able to making electrodes having largelength-to-width ratios. Additionally, by notching the first tab gap 132and the second tab gap 134, the apparatus 110 is able to createelectrodes with large tabs while significantly reducing, or nearlyeliminating, the amount of waste from the foil 114.

The processes illustrated in FIG. 4 may be entirely linear, continuous,or both. Alternatively, there may be interruptions in the processes andthe processes may split or spread onto different lines or paths. Forexample, after splitting the coated foil 114, the first and second foilsmay be recoiled and moved to separate machinery for separation of thefirst coated blank 142, the second coated blank 144, notching, orcombinations thereof.

The detailed description and the drawings or figures are supportive anddescriptive of the subject matter discussed herein. While some of thebest modes and other embodiments have been described in detail, variousalternative designs, embodiments, and configurations exist.

1. A method of forming batteries, comprising: feeding a first foilthrough a coating machine, wherein movement of the first foil defines afoil direction; applying a first coating band to the first foil;applying a second coating band to the first foil, wherein the secondcoating band is spaced from the first coating band by a first tab gap;cutting the first foil substantially perpendicular to the foil directionto separate a first coated blank; and cutting the first coated blank to:separate the first coating band and a first portion of the first tabgap; and separate the second coating band and a second portion of thefirst tab gap, wherein a first electrode is formed from the firstcoating band and the first portion of the first tab gap, and a secondelectrode is formed from the second coating band and the second portionof the first tab gap.
 2. The method of claim 1, wherein a length of thefirst electrode and the second electrode is aligned with the foildirection and a width of the first electrode and the second electrode issubstantially perpendicular to the foil direction, and wherein thelength to width ratio of the first electrode and the second electrode isat least five.
 3. The method of claim 2, wherein the first portion andthe second portion of the first tab gap are substantially equal to theentire first tab gap.
 4. The method of claim 3, wherein the secondcoating band is at least twice as wide as the first coating band, andfurther including: applying a third coating band to the first foil,wherein the third coating band is spaced from the second coating band bya second tab gap; cutting through the second coating band substantiallyparallel to the foil direction to separate the first coating band, thefirst tab gap, and a portion of the second coating band into a firstroll, and the third coating band, the second tab gap, and the remainderof the second coating band into a second roll; cutting the second rollsubstantially perpendicular to the foil direction to separate a secondcoated blank; and cutting the second coated blank to: separate the thirdcoating band and a third portion of the second tab gap from theremainder of the second coating band and a fourth portion of the secondtab gap, wherein the third portion and the fourth portion of the secondtab gap are substantially equal to the entire first tab gap, such that athird electrode is formed from the third coating band and the thirdportion of the second tab gap, and a fourth electrode is formed from theremainder of the second coating band and the fourth portion of thesecond tab gap.
 5. The method of claim 4, wherein the first foil isformed of one of aluminum alloy and copper alloy.
 6. The method of claim5, wherein the first coating band, the second coating band, and thethird coating band are formed from the same material, which is one of ananodic material and a cathodic material.
 7. The method of claim 6,further comprising: feeding a second foil through the coating machine inthe foil direction; applying a fourth coating band to the second foil;applying a fifth coating band to the second foil, wherein the fifthcoating band is spaced from the fourth coating band by a third tab gap;cutting the second foil substantially perpendicular to the foildirection to separate a third coated blank; and cutting the third coatedblank to: separate the fourth coating band and a first portion of thethird tab gap; and separate the fifth coating band and a second portionof the third tab gap, wherein a fifth electrode is formed from thefourth coating band and the first portion of the third tab gap, and asixth electrode is formed from the fifth coating band and the secondportion of the third tab gap.
 8. The method of claim 7, wherein thefirst foil is formed of aluminum alloy and the second foil is formed ofcopper alloy.
 9. The method of claim 8, wherein the first coating band,the second coating band, and the third coating band are formed from thecathodic material, and the fourth coating band and the fifth coatingband are formed from the anodic material.
 10. A method of formingbatteries, comprising: feeding a first foil through a first coatingmachine, wherein movement of the first foil defines a foil direction;applying a first coating band to the first foil; applying a secondcoating band to the first foil, wherein the second coating band isspaced from the first coating band by a first tab gap; cutting the firstfoil substantially perpendicular to the foil direction to separate afirst coated blank; cutting the first coated blank to: separate thefirst coating band and a first portion of the first tab gap, to form afirst electrode having a first tab; and separate the second coating bandand a second portion of the first tab gap, to form a second electrodehaving a second tab, wherein a length of the first electrode and thesecond electrode is aligned with the foil direction and a width of thefirst electrode and the second electrode is substantially perpendicularto the foil direction, and wherein the length to width ratio of thefirst electrode and the second electrode is at least five; feeding asecond foil through a second coating machine, wherein movement of thesecond foil defines a foil direction; applying a third coating band tothe second foil; applying a fourth coating band to the second foil,wherein the fourth coating band is spaced from the third coating band bya second tab gap; cutting the second foil substantially perpendicular tothe foil direction to separate a second coated blank; cutting the secondcoated blank to: separate the third coating band and a first portion ofthe second tab gap, to form a third electrode having a third tab; andseparate the fourth coating band and a second portion of the second tabgap, to form a fourth electrode having a fourth tab, wherein a length ofthe third electrode and the fourth electrode is aligned with the foildirection and a width of the third electrode and the fourth electrode issubstantially perpendicular to the foil direction, and wherein thelength to width ratio of the third electrode and the fourth electrode isat least five; and pairing the first electrode and the third electrodeto form a first mono cell, wherein the first tab and the third tab areon opposite sides of the width of the first electrode and the thirdelectrode.
 11. The method of claim 10, further comprising: pairing thesecond electrode and the fourth electrode to form a second mono cell,wherein the second tab and the fourth tab are on opposite sides of thewidth of the second electrode and the fourth electrode; and
 12. Themethod of claim 11, further comprising: pairing the first mono cell andthe second mono cell, wherein the first tab and the second tab are onopposite sides of the length of the first electrode and the secondelectrode and the third tab and the fourth tab are on opposite sides ofthe length of the third electrode and the fourth electrode.
 13. Themethod of claim 12, wherein the first portion and the second portion ofthe first tab gap are at least ninety percent of the length of the firsttab gap, and the t portion and the second portion of the second tab gapare at least ninety percent of the length of the second tab gap.
 14. Themethod of claim 13, wherein: the first foil is formed of aluminum alloy;the second foil is formed of copper alloy; the first coating band andthe second coating band are formed of cathodic material; and the thirdcoating band and the fourth coating band are formed of anodic material.15. The method of claim 10, wherein the first portion and the secondportion of the first tab gap are at least ninety percent of the lengthof the first tab gap, and the t portion and the second portion of thesecond tab gap are at least ninety percent of the length of the secondtab gap.
 16. The method of claim 15, wherein: the first foil is formedof aluminum alloy; the second foil is formed of copper alloy; the firstcoating band and the second coating band are formed of cathodicmaterial; and the third coating band and the fourth coating band areformed of anodic material.